Cryptonote from an architectural standpoint is an attempt to take the Bitcoin architecture and make it as private as possible at all costs. In that process it has sacrificed most of the key features that make Bitcoin viable - such as some element of security / trustless operation when not using a fullnode (i.e. mobile), scalability, usability and an open ledger where everyone from merchants to consumers can see where funds are moving to on the chain without needing a full local chain to scan every tx just to find a balance.
Dash's main goal is to improve the existing level of scalability, usability and decentralization in Bitcoin, not make these things worse. If we tried to implement the Cryptonote architectural paradigm, we would be going backwards from Bitcoin, no security for mobile wallets, no SPV, no electrum, no multisig, no Evolution, not lightening network, no decentralized governance, no instant transactions - just private transactions between desktop fullnodes with a blockchain growing many times faster and extremely slow processing of anything to do with transactions / wallets to the point where any kind of decentralized or secure ecosystem becomes impossible (see MyMonero.com).
In pretty much every area outside of sending private transactions between desktop fullnodes, Cryptonote is unviable in my view, and I doubt any Cryptonote chain would survive any large transaction volume without the network grinding to a halt. Trying to steer Dash towards Cryptonote would be like taking a ferrari and bolting 5 tons of steal on the outside and saying 'look how safe it is, everyone is going to drive these'. It means our transactions are not "as private" as cryptonote ones, but the level of privacy in Dash is still far better than Bitcoin anonymization technologies that have been sufficient for the markets that need them to date - Dash has the best privacy users are going to get on a Bitcoin based technology that they can still use safely outside of a desktop computer and has proven cryptography, scalability and all the other features that we need as a base to provide a usable currency for mainstream users. That should be good enough for us, and is just one of many features, our main one is making crypto usable - Cryptonote is as far away from that as is possible